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Opcode number: 133
Byte representation: 0x85
Short description: Fail the script unconditionally, does not even need to be executed.

OP_OR is a disabled opcode in the bitcoin scripting system.

Historical Context

Originally, OP_OR was intended to perform a bitwise OR operation on the top two items on the stack. This operation would take two numbers and produce a new number. In this result, each bit is the logical OR of the corresponding bits in the input numbers.

However, as part of a broader effort to reduce potential vulnerabilities and to simplify bitcoin's scripting language, OP_OR was disabled early in bitcoin's history along with several other opcodes.


Because OP_OR is disabled, any script that includes it will result in the transaction being declared invalid, irrespective of the script's overall context.